What to do about Ermor ....

[Boron]

for jotunheim iron woods ae ermor is evil .
ways to kill ermorian hordes really fast :
- preach
- dust to dust / wither bones
- holy pyre
- mass damage spells : especially storm / wrathful skies combo
- lighning spells ( e.g. orb lighning ) and fire spells . they in general target either a area or have a number of effects >1
- blade wind is an excellent anti ermorhordes spell too

in your current game i would do the following :
leave ermor alone , on your borders with ermor castle all + build temples and have pd + indy priests guarding the border + 1 emergency squad .

kill all other ais first . then you should have a bigger empire and lots of indy mages which have good magics against ermor .

then build some special semiscs and enjoy

example : airqueens , with staff of storm , cast wrathful skies , take some lighning immune troops with ( the air queens summons , spring hawks , storm demons ) and script the airqueens to e.g. massive orb lighnings .

or you can lategame do 2-3 flames from the sky on the ermor legions with 1000+ undeads and they will be reduced too 300 or so and easy to kill

the easiest way to kill the undead hordes are vampires / vampire lords .
when you leave ermor alone now lategame you can wish for blood and build a pack of them . they will wreak havoc on ermor . you can wish for dominion then too to ensure that your vampires always fight in positive dominion
finally you can wish for armaggedon it kills 20% of ermors troops but your jotuns and other tough troops survive because it most likely kills only weak troops .
so you will lose per armaggedon about 1-10 units while ermor loses about 20% so some thousand .
finally there is a global i think it is called purgatory which kills undeads in all provinces where you have positive dominion . since ermor can't preach and you have more territory in the long run you will outdominion ermor .